What is blue carbon?

Carbon dioxide is a greenhouse gas that occurs naturally in our atmosphere. 

It plays an important role in absorbing and radiating heat to keep temperatures on Earth stable. But carbon dioxide levels have been steadily rising, due mainly to the burning of fossil fuels, trapping more heat in our atmosphere and contributing to climate change. 

Our oceans, coral reefs and connected coastal ecosystems like seagrass meadows, mangroves and wetlands play an important role in removing carbon dioxide from our atmosphere. Known as “carbon sinks”, these diverse habitats act like enormous sponges, continually cleaning our air by absorbing carbon and storing it internally. 

Land-based ecosystems like rainforests also act as carbon sinks, but the “blue” ocean and coastal ecosystems supercharge the process, storing carbon at a much faster rate.  

Our Great Barrier Reef ecosystem is one of the world’s most powerful blue carbon sites and plays an important role. Evidence suggests that when coral reefs are damaged, the ability of nearby seagrass meadows and other coastal ecosystems to absorb carbon is also diminished. 

Tiny photosynthetic cells inside plants and coral are masters at storing carbon. All green plants — including seagrass, mangroves and the algae that live inside coral — are able to absorb carbon dioxide molecules from the air and turn them into food and energy, in a process known as photosynthesis.  

The ocean’s surface also naturally dissolves carbon dioxide molecules from the atmosphere above, collecting almost one third of all global carbon dioxide emissions.  

Over time, the carbon builds up and is deposited in coastal sediments and soils. Carbon found in our coastal ecosystems can be thousands of years old.